Dellorto Float level?

[SED]

PHF.  This is something I thought I knew how to do...

18mm + or - 0.5 sitting face down on bench with float arm vertical and lightly closing the float needle.  (by the book)   

However, new white plastic floats (9g) give a measure of 20mm, as do un-adjusted (10g) black floats.  This does not compress the float needle plunger much however.  (BTW this is with new floats, float needle and seat, and gasket under the seat)

It runs better at the 20mm setting but the plugs still show evidence excessively high fuel level so I'm thinking of increasing it to 22mm. 

Should the needle plunger be compressed all the way when measuring the 18mm distance?  This seems counter to all the references I can find.   

Thanks!
Shawn



 

[JoeW]

I always set them with the carb held sideways with the float hanging from the pivot pin. Float tab just touching the needle plunger. FYI, I've had trouble with the white floats, they do not like ethanol.

[SED]

Thanks Joe,

The white floats are nearly new.  I had them in a short time, then found the black ones on MG Cycle so installed them instead. 

Measuring it like you gives a float distance of 25mm!  Compressing the float needle plunger all the way gave 15 or 16mm so I just compressed it all the way and adjusted it to 18mm.  If I measure like the book the new distance is 21-22mm.  Test ride is positive and plugs look more normal with cleaner acceleration from low throttle, no popping through the carbs and less rumbling in the exhaust on the overrun. 

Still curious why it seems to want the float needle plunger compressed all the way.

Thanks for your help!
Shawn

[Stevex]

I set my PHF's on their side with the needle just kissing the seat without the spring depressed.
You can tell when the seat of the needle is 'home' by gently blowing through a tube connected to the fuel inlet; when it's seated you won't be able to blow through the pipe any more. This procedure will also make you aware if the needle's worn and letting by.